const kSHA1_CID = "@mozilla.org/sha1service;1";
const kSHA1_UID = Components.ID("8abf9999-7546-4add-83a3-7dbd30df5542");
const nsISHA1Service = Components.interfaces.nsISHA1Service;
const nsISupports = Components.interfaces.nsISupports;

/*
 * Configurable variables. You may need to tweak these to be compatible with
 * the server-side, but the defaults work in most cases.
 */

var hexcase = 0;  /* hex output format. 0 - lowercase; 1 - uppercase       */
var b64pad  = "=";/* base-64 pad character. "=" for strict RFC compliance  */

const _DEBUG = true;
const _NKEYS = 64;
const chrsz = 8;

function nsSHA1Service ()
{
}

nsSHA1Service.prototype.hex_sha1=function(s){return binb2hex(core_sha1(str2binb(s),s.length * chrsz));}
nsSHA1Service.prototype.b64_sha1=function(s){return binb2b64(core_sha1(str2binb(s),s.length * chrsz));}

/*
 * Calculate the SHA-1 of an array of big-endian words, and a bit length
 */
core_sha1 = function (x, len)
{
  /* append padding */
  x[len >> 5] |= 0x80 << (24 - len % 32);
  x[((len + 64 >> 9) << 4) + 15] = len;

  var w = Array(80);
  var a =  1732584193;
  var b = -271733879;
  var c = -1732584194;
  var d =  271733878;
  var e = -1009589776;

  for(var i = 0; i < x.length; i += 16)
  {
    var olda = a;
    var oldb = b;
    var oldc = c;
    var oldd = d;
    var olde = e;

    for(var j = 0; j < 80; j++)
    {
      if(j < 16) w[j] = x[i + j];
      else w[j] = rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);
      var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)),
                       safe_add(safe_add(e, w[j]), sha1_kt(j)));
      e = d;
      d = c;
      c = rol(b, 30);
      b = a;
      a = t;
    }

    a = safe_add(a, olda);
    b = safe_add(b, oldb);
    c = safe_add(c, oldc);
    d = safe_add(d, oldd);
    e = safe_add(e, olde);
  }
  return Array(a, b, c, d, e);
}

/*
 * Perform the appropriate triplet combination function for the current
 * iteration
 */
function sha1_ft(t, b, c, d)
{
  if(t < 20) return (b & c) | ((~b) & d);
  if(t < 40) return b ^ c ^ d;
  if(t < 60) return (b & c) | (b & d) | (c & d);
  return b ^ c ^ d;
}

/*
 * Determine the appropriate additive constant for the current iteration
 */
function sha1_kt(t)
{
  return (t < 20) ?  1518500249 : (t < 40) ?  1859775393 :
         (t < 60) ? -1894007588 : -899497514;
}

/*
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally
 * to work around bugs in some JS interpreters.
 */
function safe_add(x, y)
{
  var lsw = (x & 0xFFFF) + (y & 0xFFFF);
  var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
  return (msw << 16) | (lsw & 0xFFFF);
}

/*
 * Bitwise rotate a 32-bit number to the left.
 */
function rol(num, cnt)
{
  return (num << cnt) | (num >>> (32 - cnt));
}

/*
 * Convert an 8-bit or 16-bit string to an array of big-endian words
 * In 8-bit function, characters >255 have their hi-byte silently ignored.
 */
function str2binb(str)
{
  var bin = Array();
  var mask = (1 << chrsz) - 1;
  for(var i = 0; i < str.length * chrsz; i += chrsz){
    bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (24 - i%32);
  }
  return bin;
}

/*
 * Convert an array of big-endian words to a hex string.
 */
function binb2hex(binarray)
{
  var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
  var str = "";
  for(var i = 0; i < binarray.length * 4; i++)
  {
    str += hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8+4)) & 0xF) +
           hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8  )) & 0xF);
  }
  return str;
}

/*
 * Convert an array of big-endian words to a base-64 string
 */
function binb2b64(binarray)
{
  var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  var str = "";
  for(var i = 0; i < binarray.length* 4; i += 3)
  {
    var triplet = (((binarray[i   >> 2] >> 8 * (3 -  i   %4)) & 0xFF) << 16)
                | (((binarray[i+1 >> 2] >> 8 * (3 - (i+1)%4)) & 0xFF) << 8 )
                |  ((binarray[i+2 >> 2] >> 8 * (3 - (i+2)%4)) & 0xFF);
    for(var j = 0; j < 4; j++)
    {
      if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;
      else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);
    }
  }
  return str;
}

nsSHA1Service.prototype.QueryInterface = function(iid) {
  if (!iid.equals(nsISHA1Service) &&
      !iid.equals(nsISupports))
    throw Components.results.NS_ERROR_NO_INTERFACE;
  return this;
}

var jSHA1Service = new nsSHA1Service();

/**
 * JS XPCOM component registration goop:
 *
 * We set ourselves up to observe the xpcom-startup category.  This provides
 * us with a starting point.
 */

var nsSHA1ServiceModule = new Object();

nsSHA1ServiceModule.registerSelf = function (compMgr, fileSpec, location, type) {
  dump("\n Registering nsSHA1Service ...");
  compMgr = compMgr.QueryInterface(Components.interfaces.nsIComponentRegistrar);
  compMgr.registerFactoryLocation(kSHA1_UID,
                                  "nsSHA1Service",
                                  kSHA1_CID,
                                  fileSpec, 
                                  location, 
                                  type);
  dumpString("ok \n")
}

nsSHA1ServiceModule.getClassObject = function (compMgr, cid, iid) {
  if (!cid.equals(kSHA1_UID))
    throw Components.results.NS_ERROR_NO_INTERFACE;

  if (!iid.equals(Components.interfaces.nsIFactory))
    throw Components.results.NS_ERROR_NOT_IMPLEMENTED;

  return nsSHA1ServiceFactory;
}

nsSHA1ServiceModule.canUnload = function (compMgr) {
  // cleanup
  return true;
}

var nsSHA1ServiceFactory = new Object();

nsSHA1ServiceFactory.createInstance = function (outer, iid) {
  if (outer != null)
    throw Components.results.NS_ERROR_NO_AGGREGATION;

  if (!iid.equals(nsISHA1Service) &&
      !iid.equals(nsISupports))
    throw Components.results.NS_ERROR_NO_INTERFACE;
  return jSHA1Service;
}

function NSGetModule(compMgr, fileSpec) {
  return nsSHA1ServiceModule;
}
/*
  Helper Functions
*/

function dumpString(aMsg){
if(_DEBUG)
    dump(aMsg  + "\n");
}